I’m fundamentally happy with the flexibility and organization of the UI. A facelift would be nice, and I wholeheartedly think that it needs to be more a11y friendly since it’s literally impossible to use without a mouse, but overall I think it works well once you know where things are and what they do.
The bigger issue, in my opinion, is that it’s overwhelming to new users, especially those who are already struggling with their HTML and CSS skills. There are so many panels, options, choices, and decisions to make with very little handholding.
Take the margin and padding control, for example. The tab order was probably set by a drunken sailor, but it’s otherwise exactly what I need and nothing I don’t need. There are no pre-defined units constraining me, it’s visually easy to see the box model, and the equals signs make it simple to set one value and use it for all sides. Plus, the logic behind the scenes even converts to shorthand syntax.

Compare it to this abomination from Webflow, and you’ll see how much more efficient Pinegrow’s control is as long as you know what to put in those little boxes.

And even Brick Builder for WordPress uses two controls for some unknown reason.

And this is just one example.
Is the Pinegrow UI perfect? Not by a long shot. Can it be improved? Absolutely! I would hate to see any UI changes come at the expense of efficiency for the sake of beginner-friendliness or take away from other critical fixes/features the team is working on.